This invention generally relates to the guiding catheters for advancing and delivering intraluminal therapeutic and diagnostic devices within a patient""s body lumen and more specifically to a guiding catheter for providing coronary artery access for a variety of coronary procedures including angioplasty, stent delivery and the like.
In a typical coronary procedure, a guiding catheter having a preformed distal tip is percutaneously introduced into a patient""s peripheral artery, e.g. femoral or brachial artery, by means of a conventional Seldinger technique and advanced therein until the distal tip of the guiding catheter is seated in the ostium of a desired coronary artery. An elongated therapeutic or diagnostic device such as a balloon dilatation catheter or a stent delivery catheter are advanced through the inner lumen of the guiding catheter into one of the patient""s coronary arteries.
Further details of devices associated therewith for various interventional procedures can be found in U.S. Pat. No. 4,748,986 (Morrison et al.); U.S. Pat. No. 4,538,622 (Samson et al.): U.S. Pat. No. 5,135,503 (Abrams); U.S. Pat. No. 5,341,818 (Abrams et al.); and U.S. Pat. No. 5,345,945 (Hodgson et al.) which are hereby incorporated herein in their entirety by reference thereto.
The typical guiding catheter has an inner tubular layer and outer tubular layer and a tubular reinforcing layer of braided wire or ribbon disposed within the wall defined by the inner and outer layer. Frequently, the braided reinforcement layer is embedded in one or both of the inner and outer layers depending upon the manufacturing processing utilized. The distal tip of the guiding catheter is preferably formed of relatively soft polymeric material to avoid traumatic engagement with the walls or the blood vessel or the coronary ostium. The soft tip may be formed of a separate tip which is secured to the distal end of the catheter or may be an extension of one or more of the layers that form the catheter walls. Typically, the braided reinforcement layer terminates proximal to the distal end of the guiding catheter and the distal end of the reinforcement layer lies in a plane perpendicular to the longitudinal axis of the catheter. The ends of the individual wires or strands at the distal end of the braided reinforcement are welded or otherwise secured to adjacent braided structure.
During the course of an intraluminal procedure, an intraluminal device, such as a balloon catheter, atherectomy catheter, and the like, may be introduced through the guiding catheter into the vessel or body lumen. Following the intraluminal procedure, the intraluminal device is usually withdrawn through the guiding catheter distal tip. Frequently, however, the operating portion of the intraluminal device presents a larger profile upon withdrawal than when delivered. For example, with balloon catheters for angioplasty or stent delivery, the balloons on the catheters are larger in one or more transverse dimensions after inflation than when passing through the guiding catheter which can make the withdrawal of the deflated balloon back into the interior of guiding catheter problematic. Withdrawal of the intraluminal device into the guiding catheter and then withdrawal of the guiding catheter and the device together is usually preferred.
What has been needed is some way to facilitate reentry of the intraluminal device back into the inner lumen of the guiding catheter. The present invention satisfies these and other needs.
The invention is generally directed to a guiding catheter for delivery of intraluminal devices which has an elongate tubular body with a multistrand braided reinforcing structure disposed within the wall forming the tubular body. The distal end of the braided reinforcing structure lies in a plane at an angle with respect to the longitudinal axis of the tubular body of the catheter that deviates from a plane perpendicular to the longitudinal axis. The deviation angle for the distal end should be at least 10xc2x0 preferably at least 30xc2x0 from the plane perpendicular to the catheter axis. This braided reinforcing structure facilitates the retraction of an intraluminal device, such as a balloon catheter for angioplasty or stent delivery. The angle of the braid opening may follow the braid lay-up angle (the angle characteristic of the wire or ribbon comprising the braided reinforcing layer), or may be at an angle independent of the lay-up angle. The strands (wires or ribbons) of the braided reinforcement may be bonded or welded at the braid terminal end to bond the individual wires or ribbons to the adjacent wires or ribbons.
The guiding catheter of the invention comprises a tubular reinforcing layer of braided wire or ribbon disposed about an inner layer and an outer layer disposed about the braided reinforcement layer. The distal end of the guiding catheter, i.e. the portion distal to the braided reinforcement layer is formed of relatively soft material to prevent traumatic engagement with the lining of body lumens through which the guiding catheter is advanced. The reinforcement layer has a plurality of wires or ribbons braided about the inner layer at a characteristic braid angle, typically in a plurality of interwoven helices of both clockwise and counterclockwise orientation with respect to the longitudinal axis of the catheter. Conventional braiding mechanisms may be used to produce the braided layer.
The distal end of the braided reinforcement is at an angle with respect to the longitudinal axis of the catheter so the opening at the distal end of the braided reinforcement presents a generally elliptical opening with a greater surface area than an opening which lies in a plane perpendicular to the longitudinal axis which is generally circular in shape. Note that the xe2x80x9copeningxe2x80x9d referenced is the effective end of the braided reinforcement, since typically the softer and more compliant tip material and/or liner extends distally of the braid. The angled and larger opening in the braided reinforcement provides less abrupt and easier transition for the balloon or other device being withdrawn into the catheter, and thus assists the withdrawal. The inner liner may also have an similarly angled terminal end. The portion of the catheter distal to the angled distal tip of the braided reinforcement structure is pliable enough so that it does not interfere significantly with the expanded distal opening provided by the angled distal tip of the reinforcement.